(a) Field of the Invention
The present invention relates to a non-aqueous electrolyte additive for improving safety and a lithium ion secondary battery comprising the same, and more particularly to a non-aqueous electrolyte additive that can improve cycle life and safety properties of a lithium ion secondary battery.
(b) Description of the Related Art
In concert with the development of the information electronics industry, studies regarding batteries, which are referred to as the heart of all electronic equipment, are actively in progress. Specifically, a lithium ion secondary battery with a light weight and a high capacity has attracted attention as one of the essential parts of electronic equipment with the miniaturization of high-technology electronics equipment.
The lithium ion secondary battery uses a transition metal complex oxide such as lithium, cobalt, etc. as a cathode active material; a crystallized carbon such as graphite as an anode active material; and an aprotic organic solvent in which lithium salts such as LiClO4, LiPF6, etc. are dissolved as an electrolyte. Such a battery has high performance and a light weight, rendering it suitable as a battery for miniature electronic equipment such as cellular phones, camcorders, notebook computers, etc. However, this battery has many safety problems since it does not use an aqueous electrolyte but instead uses a highly flammable organic solvent as an electrolyte. Safety is the most important aspect of a lithium ion secondary battery using a non-aqueous electrolyte, and specifically, preventing short circuits and overcharging problems are very important factors thereof.